Extended Data Fig. 2: Historical irrigation withdrawals by source and projected future changes (RCP8.5-SSP3).
From: South Asian agriculture increasingly dependent on meltwater and groundwater
a) Average contribution of glacier and snowmelt (GS) contribution to irrigation withdrawal during 1981–2010 (IWREF). Grid cells with IWREF < 10 mm yr−1 are excluded. b) RCP8.5-SSP3 ensemble mean of projected changes in GS contribution to irrigation withdrawal for 2071–2100 vs 1981–2010. c) Thirty-year average monthly irrigation withdrawals for the Indus, Ganges and Brahmaputra basins during 1981–2010 differentiated by source. GS = glacier and snowmelt, RB = rainfall-runoff and baseflow, GW = groundwater. Black line indicates RCP8.5-SSP3 ensemble mean of projected change in average monthly total irrigation withdrawal 2071–2100 vs 1981–2010 (ΔIW). Error bars indicate the ensemble spread in projections. d) Average monthly projected changes in irrigation withdrawal per source for 2071–2100 vs 1981–2010 (ΔIW). Lines and shading indicate the ensemble mean and ensemble range for RCP8.5-SSP3. Upstream and downstream river basin boundaries (light grey tones) and main rivers (dark grey tones) are indicated in panels a and b. Background digital elevation model (GTOPO30) from ref. 45. River data from ref. 46.
